Consequently, every performer has his or her own way of doing voice-overs. “From all my years of nightclub comedy, I never felt comfortable sitting,” says Cook, who’d wail and flail on the Disney soundstage to give the team exactly what it needed. “I wanted to bring that live, spontaneous, improvisational aspect of stand-up to the part by literally, um, standing up.” Keach — who plays Skipper, a reclusive WWII Navy Corsair and Dusty’s flying coach, takes a different approach. “I like to perch on a stool rather than standing or sitting. I can look through the glass into the next room where the director is watching and see if he’s happy with the take or wants me to do it again.”

A multiplatform performer, Keach is an old hand at narration on CNBC specials (including one about Pixar), as well as episodes of The Simpsons and What’s New, Scooby-Doo?, balancing voice work with traditional TV parts (Prison Break), films (The Bourne Legacy) and video games. Says the longtime thespian, “There was a period when voice-overs were considered second-rate, kind of like acting in soap operas. But it’s gone completely in the opposite direction now — doing voice-over and narration can actually enhance an actor’s potential to land other jobs.”

Keach loves voice acting because he needn’t worry about looking pretty. “I don’t have to wear makeup,” he says. “I can come in dressed in sweatpants if I want to, and my sessions are generally a little more than three hours.” Of course, that doesn’t mean he’s a slacker. “I gave my all to Skipper, just as if I was performing Hamlet,” he insists. “Voice acting is not necessarily more difficult than a stage piece, but it does have its own demands and its own set of ­responsibilities. It’s definitely not something you can phone in.”

Cleese has his own rules for voice-overs. He won’t schedule early-morning sessions before he has time to “clear the tubes, as we say, of little bits of spittle or saliva in the mouth.” He’s learned to pace himself, depending on the project. Slower, soft-spoken narration, as in the ambling opening for Winnie the Pooh, requires more Zen than aggressive parts such as Skipper, whose hard-charging dialogue calls for mustering far more energy. “You have to project these animated roles and use your vocal cords far more than if you were playing the scene for real,” he says. “As a result, your voice can get tired after just a couple of hours.”

Cleese probably won’t have much time to rest, however. Disney doesn’t confirm future projects but, according to Hall, “there are lots of things that are boiling.” If Disney’s Planes is a hit, fans may see more films featuring the high-flying crew — and the legion of stars who bring it to life.

Jeffrey Ressner is a Los Angeles–based writer who has worked for Time, Rolling Stone, Politico and The Hollywood Reporter, among other publications. His favorite animated movies are The Incredibles and the original Pinocchio.